Recipe problems are the perfect conceptual introduction to direct proportion for many students. As long as learners are competent multipliers and dividers, they will be able to complete Recipes (A).
Here students have 6 recipe cards to either scale up or down. To scale up, students may have to multiply ingredients by either 2 or 3 and to scale down will be dividing by 2. However, learners will have to discover these scale factors for themselves.
Recipes (A) comes with the challenge of working with some fractional ingredients. For example, 1½ has to be halved and ½ has to be multiplied by 3.